Koalas rest on a tree at the Chimelong Safari Park in Guangzhou, South China's Guangdong province, April 29, 2019. A group of six koalas from Australia were introduced in the Guangzhou Chimelong Safari Park in 2006. After 13 years of introducing and breeding, the number of koalas in the park has reached 60 now. [Photo/Xinhua]

Koalas rest on a tree at the Chimelong Safari Park in Guangzhou, South China's Guangdong province, April 29, 2019. A group of six koalas from Australia were introduced in the Guangzhou Chimelong Safari Park in 2006. After 13 years of introducing and breeding, the number of koalas in the park has reached 60 now. [Photo/Xinhua]

Koalas rest on a tree at the Chimelong Safari Park in Guangzhou, South China's Guangdong province, April 29, 2019. A group of six koalas from Australia were introduced in the Guangzhou Chimelong Safari Park in 2006. After 13 years of introducing and breeding, the number of koalas in the park has reached 60 now. [Photo/Xinhua]